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Letter

Improvement in sperm quality and spermatogenesis following faecal microbiota transplantation from alginate oligosaccharide dosed mice

Very recent publications in Gut and else-where1 2 suggest that gut microbiota affects fertility. The application of faecal microbiota transplantation (FMT) to modify fertility is an emerging novel area of interest.3 FMT from women with poly-cystic ovary syndrome (PCOS) leads to the disruption of ovarian function and a decrease in fertility which indicates that modification of gut microbiota may be a valuable approach in the management of PCOS.2 FMT of gut microbes, that devel-oped under a high- fat diet, into mice on a normal diet leads to the disruption of spermatogenesis and a reduction of sperm motility,1 which highlights that restoring gut microbiota may be a means of improving disturbed male infertility caused by environmental factors.1 However, to date, there are no reports that address improvements of fertility following FMT. In a recent study,4 we found that busulfan damages spermatogenesis and sperm quality, and disturbs gut microbiota as found in many other studies.5 6 Alginate oligosaccharides (AOS), a natural product with many benefits, rescues busulfan disrupted spermatogenesis by supporting gut microbiota through an increase in ‘beneficial’ bacteria4 such as Bacteroidales and Lactobacillaceae and a decrease in ‘harmful’ bacteria, such as Desulfovib-rionaceae.7 Gut microbiota from AOS dosed animals may improve spermatogen-esis through benefit to the recipients gut microbes.

To test this hypothesis, we set out to explore the beneficial improvement of sperm quality and spermatogenesis following FMT from AOS dosed animals to busulfan treated mice (online supple-mentary file 1, online supplementary figure 1). A10- FMT (busulfan plus gut microbiota from AOS 10 mg/kg mice) significantly increased sperm concentra-tion (twofold) and sperm motility (twen-tyfold) (figure 1A,B). Spermatogenesis was significantly improved by A10- FMT as shown by the germ cell marker VASA (figure 1C) in murine testicular samples. The protein level of the anti- oxidant enzyme GPX1 was higher in the A10- FMT group (online supplementary figure

2A). Moreover, A10- FMT improved gene expression related to spermatogenesis in testes (figure 2A–D; online supplemen-tary figure 2), and increased the protein levels of the most important genes for spermatogenesis (figure 2E; online supplementary table 1).8 A10- FMT improved busulfan stimulated dysbiosis of gut microbiota through an increase in the ‘beneficial’ bacteria Bacteroidales and Bifidobacteriales (online supplemen-tary figures 3 and 4; online supplemen-tary table 2).7 Furthermore, there was good correlation between gut microbiota and sperm quality (online supplementary figure 3F). A10- FMT ameliorated the blood metabolome through recovery of blood metabolites (online supplementary figures 5 and 6; online supplementary data file 1; online supplementary table 3).9 Most blood metabolites were posi-tively correlated with some of the gut microbes. The data suggested that A10- FMT may improve small intestine func-tion and gut microbiota, which assists in digestion and absorption.9 A10- FMT improved the testicular metabolome (online supplementary figures 7 and 8; online supplementary data file 2; online supplementary tables 4 and 5) to help

the recovery of spermatogenesis since unsaturated fatty acids and sphingolipids are protective for biological systems.10 Testicular metabolites and sperm quality were well correlated (online supplemen-tary figure 7H,I). It was most interesting that gut microbiota, blood metabolites and testicular metabolites were well correlated, respectively, between the A10- FMT dosed and AOS dosed studies (online supplementary figure 9; online supplementary tables 6 and 7). World-wide, 10% to 15% of couples are infer-tile and many of them have abnormal spermatogenesis.8 Many studies have tried to improve spermatogenesis using different approaches, however, there has been little progress. This investigation found a mechanistic dimension linking an improved gut microbiota with the rescue of spermatogenesis and sperm quality. Because gut microbiota and host interact in very complex ways, more work is needed to clarify the deep mech-anisms through which FMT improves spermatogenesis. The current data, for the first time, highlighted that gut microbiota could be used to treat male infertility through the improvement of spermatogenesis.

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Figure 1 Mouse sperm motility, concentration, VASA staining and apoptosis status. (A) Mouse sperm concentration. The y- axis represents the concentration. The x- axis represents the treatment (n=30/group). a,b,c means not sharing a common superscript are different (p<0.05). (B) Mouse sperm motility. The y- axis represents the percentage of cells. The x- axis represents the treatment (n=30/group). a,b,c means not sharing a common superscript are different (p<0.05). (C) Germ cell marker VASA staining for mouse testicular samples. (1) Control (dosed with saline); (2) Sa (busulfan (a single injection 40 mg/kg BW of busulfan)4 plus saline); (3) Con- FMT (busulfan plus gut microbiota from regular mice); (4) A10- FMT (busulfan plus gut microbiota from AOS 10 mg/kg dosed mice); (5) A100- FMT (busulfan plus gut microbiota from AOS 100 mg/kg dosed mice). See more detailed information in online supplementary file 1. FMT, faecalmicrobiota transplantation.

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Pengfei Zhang,1,2 Yanni Feng,3 Lan Li,2 Wei Ge,2 Shuai Yu,2,4 Yanan Hao,1,2 Wei Shen,2 Xiao Han,1,2 Dongxue Ma,2 Shen Yin,2 Yu Tian,2 Lingjiang Min,5 Zhongyi Sun,4 Qingyuan Sun,6 Hongfu Zhang,1 Yong Zhao 1,2

1State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China2College of Life Sciences, Qingdao Agricultural University, Qingdao, China3College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China4Urology Department, Peking University Shenzhen Hospital, Shenzhen, China5College of Animal Sciences and technology, Qingdao Agricultural University, Qingdao, China

6State Key Laboratory of Stem Cell and reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China

Correspondence to Dr Yong Zhao, Chinese Academy of Agricultural Sciences, Haidian District 100081, China; yzhao818@hotmail.comDr Hongfu Zhang; zhanghongfu@ caas. cn

Acknowledgements We thank the investigators and staff of the Beijing Genomics Institute (BGI) and Shanghai LUMING Biotechnology CO, LCD for technical support.

Contributors PZ, YF, LL, WG, SYu, YH, WS, XH, DM, SYi, Yt and LM performed the experiments and analysed the data. HZ and YZ designed and supervised the study. ZS, QS, HZ and YZ wrote the manuscript. All

the authors edited the manuscript and approved the final manuscript.

Funding this study was supported by the National Natural Science Foundation of China (31772408 to YZ; 31672428 to HZ).

Competing interests None declared.

Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting or dissemination plans of this research.

Patient consent for publication Not required.

Provenance and peer review Not commissioned; externally peer reviewed.

Figure 2 RNA- seq data for mouse testicular samples. (A) Heatmap summary of the differentially expressed genes in the three comparisons: control versus SA; SA versus Con- FMT; SA versus A10- FMT. (B) GO enrichment of downregulated genes in control versus SA. (C) GO enrichment of upregulated genes in SA versus A10- FMT. (D) GO enrichment of upregulated genes in SA versus Con- FMT. (E) Immunofluorescence staining (IHF) for some of the spermatogenesis related marker genes in mouse testes. (1) Control (dosed with saline); (2) Sa (busulfan (a single injection 40 mg/kg BW of busulfan)4 plus saline); (3) Con- FMT (busulfan plus gut microbiota from regular mice); (4) A10- FMT (busulfan plus gut microbiota from AOS 10 mg/kg dosed mice); see more detailed information in online supplementary file 1. AOS, alginate oligosaccharides; FMT,faecal microbiota transplantation.

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Open access this is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY- NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non- commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non- commercial. See: http:// creativecommons. org/ licenses/ by- nc/ 4. 0/.

© Author(s) (or their employer(s)) 2020. re- use permitted under CC BY- NC. No commercial re- use. See rights and permissions. Published by BMJ.

► Additional material is published online only. to view please visit the journal online (http:// dx. doi. org/ 10. 1136/ gutjnl- 2020- 320992).

PZ, YF and LL contributed equally.

To cite Zhang P, Feng Y, Li L, et al. Gut epub ahead of print: [please include Day Month Year]. doi:10.1136/gutjnl-2020-320992

Received 25 February 2020revised 27 March 2020Accepted 4 April 2020

Gut 2020;0:1–3. doi:10.1136/gutjnl-2020-320992

ORCID iDYong Zhao http:// orcid. org/ 0000- 0003- 3423- 2718

RefeRences 1 Ding N, Zhang X, Zhang XD, et al. Impairment of

spermatogenesis and sperm motility by the high- fat diet- induced dysbiosis of gut microbes. Gut 2020:pii: gutjnl-2019-319127.

2 Qi X, Yun C, Sun L, et al. Gut microbiota- bile acid- interleukin-22 axis orchestrates polycystic ovary syndrome. Nat Med 2019;25:1225–33.

3 Yurtdaş G, Akdevelioğlu Y. A new approach to polycystic ovary syndrome: the gut microbiota. J Am Coll Nutr 2019;12:1–12.

4 Zhao Y, Zhang P, Ge W, et al. Alginate oligosaccharides improve germ cell development and testicular microenvironment to rescue busulfan disrupted spermatogenesis. Theranostics 2020;10:3308–24.

5 Liu F- J, Dong W- Y, Zhao H, et al. effect of molybdenum on reproductive function of male mice treated with busulfan. Theriogenology 2019;126:49–54.

6 Stringer AM, Gibson rJ, Bowen JM, et al. Chemotherapy- induced modifications to gastrointestinal microflora: evidence and implications of change. Curr Drug Metab 2009;10:79–83.

7 Zhang C, Zhang W, Zhang J, et al. Gut microbiota dysbiosis in male patients with chronic traumatic complete spinal cord injury. J Transl Med 2018;16:353.

8 Wang M, Liu X, Chang G, et al. Single- cell rNA sequencing analysis reveals sequential cell fate transition during human spermatogenesis. Cell Stem Cell 2018;23:599–614.

9 Kim N, Nakamura H, Masaki H, et al. effect of lipid metabolism on male fertility. Biochem Biophys Res Commun 2017;485:686–92.

10 Santiago Valtierra FX, Peñalva DA, Luquez JM, et al. elovl4 and Fa2h expression during rat spermatogenesis: a link to the very- long- chain PUFAs typical of germ cell sphingolipids. J Lipid Res 2018;59:1175–89.

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